Rotavirus vaccination in southern China reduces the likelihood of rotavirus gastroenteritis among children 4 years and younger, with herd effects observed in some areas, according to research published in JAMA Network Open. However, this vaccine is not included in the country’s national immunization programs.

According to the researchers, only one rotavirus vaccine is licensed in China — Lanzhou lamb rotavirus vaccine (LLR; monovalent group A oral vaccine, Lanzhou Institute of Biological Products Co, Ltd). The vaccine is intended for annual use in children between the ages of 2 months and 3 years.

“The number of LLR vaccine doses produced and administered in China has been increasing. However, vaccine use is not geographically uniform,” Chuanxi Fu, PhD, from the Zhejiang Chinese Medical University’s School of public health, and colleagues wrote. “For example, during 2013 to 2015, over one-tenth of the country’s rotavirus vaccine was administered in Guangzhou, China.”

Fu and colleagues noted that because rotavirus vaccination is not included in the country’s national immunization program, parents and caregivers must pay out of pocket to have their child vaccinated.

Source: CDC/Andre Berro, Division of Global Migration and Quarantine

To assess the rate of vaccination against rotavirus in southern China and rotavirus gastroenteritis illness occurring between May 1, 2007, and April 30, 2016, Fu and colleagues conducted a cross-sectional, ecological study in Guangzhou. This study included children aged between 2 months and 3 years who were possibly vaccinated and children aged 4 years and older who were ineligible for vaccination.

In this area of China, there were 119,705 cases of gastroenteritis, with 33,407 attributable to rotavirus infection, the researchers said. Most patients (63.5%) were male, and most were aged younger than 4 years (95.8%). Nearly all infections occurred in urban areas (93.8%).

During the study, the median age of patients with rotavirus gastroenteritis increased from 11 months in the 2007 season to 15 months in the 2015 season. Additionally, the onset of illness, peak timing and the reduction of cases was delayed throughout the course of the study. Fu told Infectious Diseases in Children that there was a delay in seasonal distribution of disease onset, and this was observed through multi-season weekly data. The researchers could not confirm that the impact of vaccination or virus reproduction affected this delay.

In further analysis, Fu and colleagues calculated the median vaccination coverage rate in the past 12 months — 8.36% — which they used as a cutoff point to categorize high and low vaccination coverage over the study period. They noted a 32.4% decrease in gastroenteritis in children aged younger than 4 years following years with high coverage (incidence rate ratio [IRR] = 0.67; 95% CI, 0.659-0.693).

The incidence of illness among children who were ineligible for immunization against rotavirus was greater during times when immunization rates were high (IRR = 0.790; 95% CI, 0.351-0.915).

Unvaccinated children aged younger than 3 years who lived in areas with 15% to 19% immunization coverage were at greatest risk for developing rotavirus gastroenteritis (IRR = 0.85; 95% CI, 0.73-0.99). When vaccination coverage increased to 20% or more, an increased risk was still observed (IRR = 0.79; 95% CI, 0.67-0.93).

Fu and colleagues identified two barriers that may affect the rate and efficacy of LLR vaccination.

“Timing of the current regimen, in which children receive one dose per year for 3 consecutive years beginning at age 2 months, may not be ideal,” the researchers wrote. “In China, 94.5% of infants have rotavirus-associated diarrhea during the first 2 years of life, 16.9% have rotavirus infection by age 6 months and 59.1% have rotavirus infection by age 1 year. It is essential that children receive a vaccination as soon as possible to ensure the induction of protection prior to natural rotavirus infection.”

Additionally, the researchers noted that vaccination with LLR can be cost-prohibitive for families residing in the area.

“The vaccine is priced at $63 for two doses, which is almost a tenth of a worker’s average monthly salary in China,” Fu and colleagues wrote. “As a result, uptake is low and only 10% of children received two or three doses of the vaccine in Guangzhou... A cost-effectiveness model has shown that in China, a two-dose rotavirus program could annually avert [62% of] deaths, [59% of] hospitalizations and [51% of] outpatient visits associated with rotavirus disease.” – by Katherine Bortz

Disclosures: Fu reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.

Rotavirus vaccination in southern China reduces the likelihood of rotavirus gastroenteritis among children 4 years and younger, with herd effects observed in some areas, according to research published in JAMA Network Open. However, this vaccine is not included in the country’s national immunization programs.

According to the researchers, only one rotavirus vaccine is licensed in China — Lanzhou lamb rotavirus vaccine (LLR; monovalent group A oral vaccine, Lanzhou Institute of Biological Products Co, Ltd). The vaccine is intended for annual use in children between the ages of 2 months and 3 years.

“The number of LLR vaccine doses produced and administered in China has been increasing. However, vaccine use is not geographically uniform,” Chuanxi Fu, PhD, from the Zhejiang Chinese Medical University’s School of public health, and colleagues wrote. “For example, during 2013 to 2015, over one-tenth of the country’s rotavirus vaccine was administered in Guangzhou, China.”

Fu and colleagues noted that because rotavirus vaccination is not included in the country’s national immunization program, parents and caregivers must pay out of pocket to have their child vaccinated.

Source: CDC/Andre Berro, Division of Global Migration and Quarantine

To assess the rate of vaccination against rotavirus in southern China and rotavirus gastroenteritis illness occurring between May 1, 2007, and April 30, 2016, Fu and colleagues conducted a cross-sectional, ecological study in Guangzhou. This study included children aged between 2 months and 3 years who were possibly vaccinated and children aged 4 years and older who were ineligible for vaccination.

In this area of China, there were 119,705 cases of gastroenteritis, with 33,407 attributable to rotavirus infection, the researchers said. Most patients (63.5%) were male, and most were aged younger than 4 years (95.8%). Nearly all infections occurred in urban areas (93.8%).

During the study, the median age of patients with rotavirus gastroenteritis increased from 11 months in the 2007 season to 15 months in the 2015 season. Additionally, the onset of illness, peak timing and the reduction of cases was delayed throughout the course of the study. Fu told Infectious Diseases in Children that there was a delay in seasonal distribution of disease onset, and this was observed through multi-season weekly data. The researchers could not confirm that the impact of vaccination or virus reproduction affected this delay.

In further analysis, Fu and colleagues calculated the median vaccination coverage rate in the past 12 months — 8.36% — which they used as a cutoff point to categorize high and low vaccination coverage over the study period. They noted a 32.4% decrease in gastroenteritis in children aged younger than 4 years following years with high coverage (incidence rate ratio [IRR] = 0.67; 95% CI, 0.659-0.693).

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The incidence of illness among children who were ineligible for immunization against rotavirus was greater during times when immunization rates were high (IRR = 0.790; 95% CI, 0.351-0.915).

Unvaccinated children aged younger than 3 years who lived in areas with 15% to 19% immunization coverage were at greatest risk for developing rotavirus gastroenteritis (IRR = 0.85; 95% CI, 0.73-0.99). When vaccination coverage increased to 20% or more, an increased risk was still observed (IRR = 0.79; 95% CI, 0.67-0.93).

Fu and colleagues identified two barriers that may affect the rate and efficacy of LLR vaccination.

“Timing of the current regimen, in which children receive one dose per year for 3 consecutive years beginning at age 2 months, may not be ideal,” the researchers wrote. “In China, 94.5% of infants have rotavirus-associated diarrhea during the first 2 years of life, 16.9% have rotavirus infection by age 6 months and 59.1% have rotavirus infection by age 1 year. It is essential that children receive a vaccination as soon as possible to ensure the induction of protection prior to natural rotavirus infection.”

Additionally, the researchers noted that vaccination with LLR can be cost-prohibitive for families residing in the area.

“The vaccine is priced at $63 for two doses, which is almost a tenth of a worker’s average monthly salary in China,” Fu and colleagues wrote. “As a result, uptake is low and only 10% of children received two or three doses of the vaccine in Guangzhou... A cost-effectiveness model has shown that in China, a two-dose rotavirus program could annually avert [62% of] deaths, [59% of] hospitalizations and [51% of] outpatient visits associated with rotavirus disease.” – by Katherine Bortz

Disclosures: Fu reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.